Reproductive characteristics of adult channel catfish treated with trenbolone acetate during the phenocritical period of sex differentiation

Channel catfish fry fed for 60 days with 0, 50 or 100 mg/kg trenbolone acetate (TBA) and judged by dissection of fingerlings to be males were grown to sexual maturity in ponds. Body weight and gonadal development were compared when the fish were 18 months old. Trenbolone-treated fish were significantly lighter, shorter and the gonads less developed than control males. Three-year-old fish were visually examined for external sex characteristics, and sampled for gonadal development and plasma hormone concentrations. Gonad weight, GSI and plasma testosterone were significantly higher in control fish than in either of the trenbolone-treated groups. Twenty fish from each treatment group were placed in spawning cages with normal female fish. Five spawns were obtained from each of the treatment groups; however, all 10 spawns were composed of infertile eggs. TBA interferes with normal gonadal development of both the testis and ovary but does not functionally masculinize channel catfish.